Differently from polymer molded products such as films, fibers, injection molded products and extrusion molded products, polymer particles are used for modification and improvement of various materials by utilizing the large specific surface area and the structure of particles. The major use of these particles includes additives for toners, binder materials for paints and the like, additives for powder coating materials and the like, materials for coating metals, water repellent coating materials, and additives for molded articles such as automobile materials and construction materials.
Polyvinylidene difluoride particles have excellent properties such as weather resistance, stain resistance, solvent resistance, water resistance and moisture resistance, and are suitably used for applications such as a stain-resistant material in printers, a toner application, and a resin for weather-resistant or water-resistant paints.
There are some previously known methods to produce particles or powder of polyvinylidene difluoride, for example, a crushing method represented by freeze-crushing or the like, and a polymerization method in which the particles are obtained by emulsification polymerization or suspension polymerization (for example, see Patent Documents 1 to 9). However, the polymer particles or powder of polyvinylidene difluoride obtained by such a method have problems. For example, the obtained particles do not form a true spherical shape, their particle diameter cannot be controlled, and their particle diameter distribution becomes broad. Therefore, in several fields such as coating materials and paints where the uniformity and the surface smoothness of particles are important, the effect produced by addition of these particles is not satisfactory under the existing circumstances.